Species-Specific Defense Reactions (SSDRs)
Species-specific defense reactions (SSDRs) are instinctual and automatic reactions to a fearful stimulus. They are innate and occur naturally without any conscious thought from the organism. SSDRs are theorized to be an evolutionary adaptation to predators which increase the likelihood of survival.
Examples of SSDRs are freezing, fleeing, or fighting. SSDRs are very difficult to overcome as they are an innate reactions and not acquired behaviors. An example from a lab setting is that pigeons who are close to other pigeons will attack each other if they are shocked- the fearful stimulus causes an SSDR of fighting.